COMPLEX HEAT SOURCE APPARATUS

Description

BACKGROUND OF THE INVENTION

1. Technical Field

[0001] The present invention relates to a complex heat source apparatus which is made up of: first and second, i.e., a total of two, heat exchangers; a first burner for heating the first heat exchanger; and a second burner for heating the second heat exchanger.

2. Background Art

[0002] As this kind of complex heat source apparatus, there is known, e.g., in JP-A-2006-38423, a complex heat source apparatus in which both the first and the second burners are constituted by Bunsen burners such as rich and lean combustion burners and the like, and in which combustion air (primary air and secondary air) is supplied by a fan which is common to both the burners.

[0003] According to this arrangement, by making the fan to commonly serve both the burners, the costs can be reduced, but the following disadvantages exist. That is, at the time of a single operation in which only one of the first burner and the second burner is combusted to heat one of the heat exchangers corresponding to said one burner is heated, the air is supplied also to the other of the burners. This air passes, as it is, through the other heat exchanger corresponding to the other of the burners and, as a result, this heat exchanger is cooled. The thermal efficiency of this heat exchanger therefore becomes lower when the heat exchanger is heated again.

[0004] By the way, although not a complex heat source apparatus, there is known, e.g., in JP-A-2010-151395 the following heat source apparatus. That is, in a heat source apparatus having a plurality of burners for heating a single heat exchanger, the plurality of burners are constituted by totally aerated combustion burners (or "fully primary aerated burners"). In a common air supply passage connected to these burners there is interposed a single fan which supplies primary air. The downstream end of the fuel gas supply passage is connected to that portion of the air supply passage which is on an upstream side or a downstream side of the fan. It is thus so arranged that the mixture of the primary air and the fuel gas can be supplied to the plurality of burners through the air supply passage. The gas supply passage has interposed therein a flow control means which enables to vary the fuel gas feed amount in proportion to the amount of primary air supply so as to make the air-fuel ratio of the air-fuel mixture constant. Also the connection portions between each of the burners and the air supply passage are provided with on-off valves. Another related heat source apparatus is known from JP 2003 214622, disclosing a heat source apparatus comprising a heat exchanger 32,a first burner 22L for heating the heat exchanger, and a second burner 22R for heating the heat exchanger, both the first and the second burners being constituted by totally aerated (premix) combustion burners, a single fan 16 for supplying primary air, said fan being interposed in a common air supply passage 18 connected to both the first and the second burners, a gas supply passage 52 for supplying fuel gas wherein a downstream end 56 of the gas supply passage is connected to that portion of the air supply passage which is on a downstream side of the fan so that a mixture of the primary air and the fuel gas can be supplied through the air supply passage to both the first and the second burners; wherein a flow control means 51, 53, 54 interposed in the gas supply passage so as to vary the amount of fuel gas supply in proportion to the amount of primary air supply, thereby making the air-fuel ratio of the air-fuel mixture constant, an on-off valve 62R is provided at a connection portion 23R between the first burner and the air supply passage, and a valve 62L is provided at a connection portion 23L between the second burner and the air supply passage.

[0005] By applying this art to a complex heat source apparatus, the following arrangement is conceivable. That is, each of the first and the second burners to respectively heat each of the first and the second heat exchangers is constituted by a totally aerated combustion burner. The air-fuel mixture is supplied to both the first and the second burners through an air supply passage in which a single fan is interposed. Also, an on-off valve is disposed at each of the connection portion between each of the burners and the air supply passage. At the time of a single operation in which only one of the first burner and the second burner is combusted to heat one of the heat exchangers that corresponds to the said one burner, the on-off valve disposed at the connection portion between the other of the first and the second burners and the air supply passage is closed so as to stop the air-fuel mixture supply to the other burner. According to this arrangement, the other heat exchanger that corresponds to the other burner not combusted at the time of a single operation, can be prevented from being cooled by the air flow from the fan.

[0006] However, this arrangement gives rise to the following disadvantages. That is, at the time of a simultaneous operation in which both the first and the second burners are combusted for heating both the first and the second heat exchangers, when the rotational speed of the fan is changed, the amount of air-fuel mixture supply to the first burner and the amount of air-fuel mixture supply to the second burner will both be changed. As a result, the amount of air-fuel mixture supply to the first burner and the amount of air-fuel mixture supply to the second burner will no longer be adjustable independently.

SUMMARY

Problems that the Invention is to Solve

[0007] In view of the above-mentioned points, this invention has a problem of providing a complex heat source apparatus in which the amount of air-fuel supply to the first and the second burners through a common gas supply passage is independently controllable.

Means for Solving the Problems

[0008] In order to solve the above-mentioned problems, this invention has an advantage in providing a complex heat source apparatus as defined in claim 1. A particular aspect of the complex heat source apparatus is that an on-off valve is provided at a connection portion between one of the first and the second burners and the air supply passage, and that a flow control valve is provided at a connection portion between the other of the first and the second burners and the air supply passage; and that an amount of air-fuel mixture supply to said one of the burners is adjusted by a rotational speed of the fan and the amount of the air-fuel mixture supply to the other of the burners is adjusted by the rotational speed of the fan and by the flow control valve.

[0009] According to this invention, at the time of a simultaneous operation in which both the first and the second burners are combusted to thereby heat both the first and the second heat exchangers, the amount of air-fuel mixture supply to one burner out of the first and the second burners, is adjusted by the control of the rotational speed of the fan to an amount depending on the required amount of combustion at said one of the burners. Also, the amount of air-fuel mixture supply to the other of the burners can be adjusted by the control of the flow control valve to an amount depending on the required amount of combustion at the other burner. That is, the amount of air-fuel mixture supply to the first burner and the amount of air-fuel mixture supply to the second burner can be independently adjusted. Further, since the on-off valve is disposed at the connection portion between one burner and the air supply passage, the cost can be reduced as compared with an arrangement in which a flow control valve is also disposed at this connection portion.

[0010] Further, in this invention, when the first burner is made larger in rated combustion amount than the second burner, preferably the on-off valve is provided at a connection portion between the first burner and the air supply passage. According to this arrangement, even if the amount of air-fuel mixture supply to the second burner is increased or decreased by the control of the flow control valve, the amount of the air-fuel supply to the first burner that is a large-sized burner having a larger rated combustion amount does not vary so much, but the combustion amount of the first burner can be maintained at a value closer to the required amount of combustion. Therefore, precise cooperative control of the rotational speed of the fan and the flow control valve is not needed, with the result that the control becomes easier.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 is a schematic sectional view showing the complex heat source apparatus according to an embodiment of this invention.

PREFERRED EMBODIMENTS FOR CARRYING OUT THE INVENTION

[0012] A complex heat source apparatus according to an embodiment of this invention as shown in FIG. 1 is made up of: a first heat exchanger 1₁ for supplying hot water; a second heat exchanger 1₂ for space heating; a first burner 2₁ for heating the first heat exchanger 1₁; and a second burner 2₂ for heating the second heat exchanger 1₂.

[0013] Each of the first and the second burners 2₁, 2₂ is constituted by a totally aerated combustion burner which ejects and combusts air-fuel mixture of fuel gas and primary air through a multiplicity of flame holes (not illustrated) formed in a combustion plate 22 that covers one surface of a box-shaped burner body 21, and is disposed in a posture facing downward with the combustion plate 22 lying on the lower side. Each of first and second combustion boxes 3₁, 3₂ that enclose the combustion space below each of the first and the second burners 2₁, 2₂ is disposed so as to house therein each of the first and the second heat exchangers 1₁ ,1₂, respectively. Further, there is provided an exhaust duct 4 which is in communication with the lower ends of the first and the second combustion boxes 3₁, 3₂. It is thus so arranged that the combustion exhaust gases from each of the first and the second burners 2₁, 2₂ can flow through each of the first and the second heat exchangers 1₁, 1₂ into the exhaust duct 4.

[0014] By the way, since hot water supply requires a larger heating capacity than space heating, the first burner 2₁ is arranged to be a large burner having a larger rated combustion amount (maximum combustion amount) than the second burner 2₂. Further, the exhaust duct 4 is partitioned by a partition plate 41 that is disposed therein into a duct portion through which the combustion exhaust gases from the first burner 2₁ flow and the other duct portion through which the combustion exhaust gases from the second burner 2₂ flow.

[0015] Each of the first and the second heat exchangers 1₁, 1₂ is made up of: a multiplicity of heat absorbing fins 11 which are laminated with one another in the direction perpendicular to the paper surface of FIG. 1; and a snaking heat absorbing tube 12 which penetrates through these fins 11. Although not illustrated, the heat absorbing tube 12 of the first heat exchanger 1₁ has connected thereto a water supply pipe on the upstream side and a hot water delivery pipe on the downstream side. It is thus so arranged that, when a hot water faucet on the downstream side of the hot water delivery pipe is opened to let the water flow to the first heat exchanger 1₁, the first burner 2₁ is combusted, so that hot water at a set temperature is delivered from the hot water faucet. Although not illustrated, the heat absorbing tube 12 of the second heat exchanger 1₂ is connected to the heating circuit of floor heating, and the like through a forward tube and a return tube. Space heating can thus be performed by circulating hot water to the heating circuit through the second heat exchanger 1₂.

[0016] Further, the first and the second burners 2₁, 2₂ have connected thereto a common air supply passage 5. This air supply passage 5 has interposed therein a single fan 6 which supplies primary air. That portion of the air supply passage 5 which is on an upstream side of the fan 6 has connected thereto a gas outlet 71 which is on a downstream end of a gas supply passage 7 for supplying fuel gas. That portion of the of the air supply passage 5 to which the gas outlet 71 is connected is arranged to constitute a venturi portion 51 having a constricted sectional area.

[0017] The gas supply passage 7 has interposed therein a main valve 72, and a zero governor 73 as a flow control means which controls the secondary gas pressure to a pressure equivalent to the atmospheric pressure. It is to be noted here that the amount of fuel gas supply varies with a differential pressure between the atmospheric pressure which is the secondary gas pressure, and that suction negative pressure of the fan 6 which operates on the venturi portion 51. Since the suction negative pressure of the fan varies in proportion to the rotational speed of the fan, the amount of fuel gas varies in proportion to the rotational speed of the fan, i.e., the amount of the primary air supply.

[0018] Further, a connection portion 2₁a between the first burner 2₁ and the air supply passage 5 is provided with an on-off valve 8 driven by an actuator 81 such as an electromagnetic solenoid, and the like. A connection portion 2₂a between the second burner 2₂ and the air supply passage 5 is provided with a flow control valve 9 of a needle type which is driven by an actuator 91 made up of a combination of an electric motor and a feed screw mechanism.

[0019] At the time of a single operation of hot water supply in which only the first burner 2₁ is combusted to thereby heat the first heat exchanger 1₁, the on-off valve 8 opened to supply the air-fuel mixture to the first burner 2₁ and also the flow control valve 9 is totally closed to thereby stop the supply of air-fuel mixture to the second burner 2₂. Further, the amount of air-fuel mixture supply to the first burner 2₁ is adjusted by the rotational speed of the fan 6 so as to become a value corresponding to the hot water demand combustion amount (combustion amount necessary to supply hot water at a set temperature). Further, at the time of a single operation for space heating in which only the second burner 2₂ is combusted to thereby heat the second heat exchanger 1₂, the flow control valve 9 is fully opened to supply the air-fuel mixture to the second burner 2₂. The on-off valve 8 is closed to stop the supply of air-fuel mixture to the first burner 2₁. Further, the amount of air-fuel mixture supply to the second burner 2₂ is adjusted by the rotational speed of the fan 6 so as to attain a value corresponding to the space-heating demand combustion amount (combustion amount necessary to supply hot water to the space-heating circuit at a set temperature).

[0020] At the time of a simultaneous operation of hot water supply and hot air supply by combusting the first burner 2₁ for heating the first heat exchanger 1₁, and also by combusting the second burner 2₂ for heating the second heat exchanger 1₂, in a state in which the on-off valve 8 is opened, the amount of air-fuel mixture supply to the first burner 2₁ is adjusted by the rotational speed of the fan 6 so that the amount of air-fuel mixture supply becomes a value corresponding to the hot water demand combustion amount. In this case, if the flow control valve 9 is left fully opened, the amount of air-fuel mixture supply to the second burner 2₂ will fluctuate (i.e., increase or decrease) due to an increase or decrease in the rotational speed of the fan 6. As a result, the amount of combustion in the second burner 2₂ will no longer be maintained at the space-heating demand combustion amount. As a solution, in this embodiment, at the time of a simultaneous operation, the amount of air-fuel mixture supply to the second burner 2₂ is controlled by the flow control valve 9 so that the amount of air-fuel mixture supply to the second burner 2₂ becomes a value corresponding to the space-heating demand combustion amount. In this manner, also at the time of a simultaneous operation, the amount of air-fuel mixture supply to the first burner 2₁ and the amount of air-fuel mixture supply to the second burner 2₂ can be independently adjusted depending on the space-heating demand combustion amount of each of the burners 2₁, 2₂.

[0021] It is conceivable to dispose the flow control valve also at the connection portion 2₁a between the first burner 2₁ and the air supply passage 5. However, as in this embodiment, by selecting the valve disposed at this connection portion 2₁a to be the on-off valve 8, the cost reduction can advantageously be attained.

[0022] It is also conceivable to employ the following arrangement. That is, a flow control valve is disposed in the connection portion 2₁a between the first burner 2₁ and the air feed passage 5, and an on-off valve is disposed in the connection portion 2₂a between the second burner 2₂ and the air feed passage 5. At the time of a simultaneous operation in this arrangement, the amount of air-fuel mixture supply to the second burner 2₂ is controlled by the rotational speed of the fan 6, and the amount of air-fuel mixture supply to the first burner 2₁ is controlled by the flow control valve. In this arrangement, however, as a result of control of the amount of air-fuel mixture supply to the large-sized first burner 2₁, the amount of air-fuel mixture supply to the small-sized second burner 2₂ will largely be fluctuated. Accurate cooperation control of the rotational speed of the fan and control of the flow control valve will thus be required, thereby complicating the control.

[0023] According to the arrangement of this embodiment, on the other hand, even if the amount of air-fuel mixture supply to the small-sized second burner 2₂ is increased or decreased by the control of the flow control valve 9, the amount of air-fuel mixture supply to the large-sized first burner 2₁ will not vary much. As a result, the amount of combustion of the first burner 2₁ can be maintained at a value close to the required amount of combustion. Therefore, an accurate cooperative control between the rotational speed of the fan and the flow control valve 9 becomes needless, with the result that the control becomes easier.

[0024] Description has so far been made of the embodiment of this invention with reference to the accompanying drawing. This invention, however, shall not be limited to the above, but the following arrangement may be employed. For example, a venturi portion is provided in that portion of the air supply passage 5 which is on the downstream side of the fan 6. The downstream end of the gas supply passage 7 is made to lie proximate to the venturi portion. Then there may be interposed a zero governor in the gas supply passage 7 as the flow amount adjusting means, the zero governor serving to adjust the secondary gas pressure to a pressure equivalent to the outlet pressure of the fan 6. In this case, the differential pressure between the outlet pressure of the fan 6 and the venturi portion is proportional to the amount of the primary air supply by the fan 6. The amount of the fuel gas supply will also be proportional to the amount of the primary air supply.

[0025] Further, it is also conceivable to interpose a proportional valve in the gas supply passage 7 as a flow control means in order to make adjustments with the proportional valve so that the amount of the fuel gas supply is proportional to the amount of the primary air supply. In this case, the downstream end of the gas supply passage 5 may be connected to either an upstream portion or a downstream portion of the fan in the air supply passage 5. Further, the above embodiment is a complex heat source apparatus of serving the dual purposes of hot water supply and hot air supply in which the first heat exchanger 1₁ is for supplying hot water and the second heat exchanger 1₂ is for supplying hot air. However, this invention can similarly be applicable to the one in which the second heat exchanger 1₂ is other than for supplying hot air for space heating, e.g., for reheating a bath tab.

EXPLANATION OF MARKS

[0026] 

1₁

first heat exchanger

1₂

second heat exchanger

2₁

first burner

2₂

second burner

2₁a

connection portion between the first burner and the air supply passage

2₂a

connection portion between the second burner and the air supply passage

5

air supply passage

6

fan

7

gas supply passage

71

gas outlet (downstream end of the gas supply passage)

73

zero governor (flow control means)

8

on-off valve

9

flow control valve

Claims

1. A complex heat source apparatus comprising:

first and second, i.e., a total of two, heat exchangers (1₁, 1₂);

a first burner (2₁) for heating the first heat exchanger (1₁), and a second burner (2₂) for heating the second heat exchanger (1₂), both the first and the second burners (2₁, 2₂) being constituted by totally aerated combustion burners;

a single fan (6) for supplying primary air, said fan (6) being interposed in a common air supply passage (5) connected to both the first and the second burners (2₁, 2₂);

a gas supply passage (7) for supplying fuel gas wherein a downstream end (71) of the gas supply passage (7) is connected to that portion of the air supply passage (5) which is on an upstream side or on a downstream side of the fan (6) so that a mixture of the primary air and the fuel gas can be supplied through the air supply passage (5) to both the first and the second burners (2₁, 2₂); and

a flow control means (73) interposed in the gas supply passage (7) so as to vary the amount of fuel gas supply in proportion to the amount of primary air supply, thereby making the air-fuel ratio of the air-fuel mixture constant;

wherein

an on-off valve (8) is provided at a first connection portion (2₁a, 2₂a) between one of the first and the second burners (2₁, 2₂) and the air supply passage (5), and a flow control valve (9) is provided at a second connection portion (2₁a, 2₂a) between the other of the first and the second burners (2₁, 2₂) and the air supply passage (5); and

wherein the apparatus is adapted such that an amount of air-fuel mixture supply to said one of the burners is adjusted by a rotational speed of the fan (6) and the amount of the air-fuel mixture supply to the other of the burners is adjusted by the rotational speed of the fan (6) and by the flow control valve (9).

2. The complex heat source apparatus according to claim 1,
wherein the first burner (2₁) is made larger in rated combustion amount than the second burner (2₂); and
wherein the on-off valve (8) is provided at the connection portion (2₁a) between the first burner (2₁) and the air supply passage (5).

Ansprüche

1. Komplexe Wärmequellenvorrichtung, aufweisend:

erste und zweite, also insgesamt zwei Wärmetauscher (1₁, 1₂);

einen ersten Brenner (2₁) zum Erwärmen des ersten Wärmetauschers (1₁) und einen zweiten Brenner (2₂) zum Erwärmen des zweiten Wärmetauschers (1₂), wobei sowohl der erste als auch der zweite Brenner (2₁, 2₂) aus vollständig belüfteten Verbrennungsbrennem gebildet sind;

einen Einzellüfter (6) zum Zuführen von Primärluft, wobei besagter Lüfter (6) in einer gemeinsamen Luftzufuhrpassage (5) angeordnet ist, die sowohl mit dem ersten als auch mit dem zweiten Brenner (2₁, 2₂) verbunden ist,

eine Gaszufuhrpassage (7) zum Zuführen von Brenngas, wobei ein stromabwärtiges Ende (71) der Gaszufuhrpassage (7) mit demjenigen Abschnitt der Luftzufuhrpassage (5) verbunden ist, der an einer stromabwärtigen oder stomaufwärtigen Seite des Lüfters (6) ist, so dass ein Gemisch aus der Primärluft und dem Brenngas durch die Luftzufuhrpassage (5) sowohl an den ersten als auch an den zweiten Brenner (2₁, 2₂) zugeführt werden kann; und

eine Durchflussregeleinrichtung (73), die in der Gaszufuhrpassage (7) angeordnet ist, um den Betrag Brenngaszufuhr proportional zur Menge der Primärluftzufuhr zu variieren, wodurch das Luft/Brenngas-Verhältnis in dem Luft/Brenngas-Gemisch konstant wird,

wobei

ein An/Aus-Ventil (8) an einem ersten Verbindungsabschnitt (2₁a, 2₂a) zwischen dem ersten oder zweiten Brenner (2₁, 2₂) und der Luftzufuhrpassage (5) vorgesehen ist, und ein Durchflussregelventil (9) an einem zweiten Verbindungsabschnitt (2₁a, 2₂a) zwischen dem jeweils anderen des ersten und des zweiten Brenners (2₁, 2₂) und der Luftzufuhrpassage (5) vorgesehen ist; und

wobei die Vorrichtung derart eingerichtet ist, dass

ein Betrag des Luft/Brenngas-Gemischs an besagten einen der Brenner durch eine Drehzahl des Lüfters (6) eingestellt wird und die Zufuhrmenge an Luft/Brenngas-Gemisch an den anderen der Brenner durch die Drehzahl des Lüfters (6) und durch das Durchflussregelventil (9) eingestellt wird.

2. Komplexe Wärmequellenvorrichtung nach Anspruch 1,
wobei der erste Brenner (2₁) bezüglich der Nenn-Verbrennungsmenge größer ausgelegt ist als der zweite Brenner (2₂); und
wobei das An/Aus-Ventil (8) an dem Verbindungsabschnitt (2₁a) zwischen dem ersten Brenner (2₁) und der Luftzufuhrpassage (5) vorgesehen ist.

Revendications

1. Appareil à source de chaleur complexe, comprenant :

des premier et second, c'est-à-dire un total de deux, échangeurs de chaleur (1₁, 1₂) ;

un premier brûleur (2₁) destiné à chauffer le premier échangeur de chaleur (1₁), et un second brûleur (2₂) destiné à chauffer le second échangeur de chaleur (1₂); les premier et second brûleurs (2₁, 2₂) étant tous deux constitués par des brûleurs de combustion totalement aérés ;

un ventilateur unique (6) destiné à alimenter de l'air primaire, ledit ventilateur (6) étant intercalé dans un passage d'alimentation en air commun (5) raccordé aux deux premier et second brûleurs (2₁, 2₂) ;

un passage d'alimentation en gaz (7) destiné à alimenter un gaz combustible, dans lequel une extrémité aval (71) du passage d'alimentation en gaz (7) est raccordée à la portion du passage d'alimentation en air (5) qui se trouve sur un côté amont ou sur un côté aval du ventilateur (6), de sorte qu'un mélange de l'air primaire et du gaz combustible peut être alimenté par le biais du passage d'alimentation en air (5) vers les deux premier et second brûleurs (2₁, 2₂), et

un moyen de réglage de débit (73) intercalé dans le passage d'alimentation en gaz (7) de manière à faire varier la quantité d'alimentation en gaz combustible proportionnellement à la quantité d'alimentation en air primaire, ceci rendant le rapport air-combustible du mélange air-combustible constant ;

dans lequel un robinet à marche tout-ou-rien (8) est prévu sur une première portion de raccordement (2₁a, 2₂a) entre l'un parmi les premier et second brûleurs (2₁, 2₂) et le passage d'alimentation en air (5), et un robinet de réglage de débit (9) est prévu sur une seconde portion de raccordement (2₁a, 2₂a) entre l'autre parmi les premier et second brûleurs (2₁, 2₂) et le passage d'alimentation en air (5), et

dans lequel l'appareil est adapté de telle sorte qu'une quantité d'alimentation de mélange air-combustible vers ledit un des brûleurs est ajustée par une vitesse de rotation du ventilateur (6), et la quantité d'alimentation de mélange air-combustible vers l'autre des brûleurs est ajustée par la vitesse de rotation du ventilateur (6) et par le robinet de réglage de débit (9).

2. Appareil à source de chaleur complexe selon la revendication 1,
dans lequel le premier brûleur (2₁) est fabriqué plus grand, quant à la quantité de combustion nominale, que le second brûleur (2₂), et
dans lequel le robinet à marche tout-ou-rien (8) est prévu sur la portion de raccordement (2₁a) entre le premier brûleur (2₁) et le passage d'alimentation en air (5).

Drawing